Static Output Research Articles

Preparation of non-Gaussian states based on three-photon quantum scissors

We investigate the properties of non-Gaussian quantum states generated by a three-photon quantum scissor (3-QS). Three different types of inputs to the 3-QS are considered: coherent state (CS), squeezed vacuum state (SVS), and optical field thermal state (TS). We discuss both the detection probability and fidelity of the output states. Our results demonstrate that when the input states have a smaller mean photon number, the output non-Gaussian state can exhibit high detection probability and high fidelity by selecting an appropriate transmissivity. Additionally, we calculate the Wigner functions for the various output states and analyze the non-classical properties by comparing the negative volume of the Wigner functions. The results indicate that the output non-Gaussian states display significant non-classical behavior, particularly when the transmissivity is high, with SVS as the input state showing the strongest effect. Moreover, we compare the performance of the 3-QS with that of the two-photon quantum scissors (2-QS). The findings demonstrate that the non-Gaussian states prepared by the 3-QS possess stronger non-classical characteristics. These results have potential implications for advancing the practical application of the 3-QS in quantum information technology.

Abstract 12955: Shear-Dependent Changes in Blood Viscosity Negatively Affect Energetic Efficiency in Patient-Specific Models of the Fontan Circulation

Introduction: Since blood flow through the lungs is passive in patients with the Fontan circulation, cardiac output is sensitive to power loss through the pulmonary vasculature. Prior small in vitro studies of how changes in blood viscosity at venous shear rates (“non-Newtonian behavior”) affect power loss have yielded conflicting results. The purpose of this study was to evaluate the extent to which non-Newtonian behavior contributes to power loss in a large number of pediatric patient-specific models of the Fontan circulation. Hypothesis: Shear-dependent changes in blood viscosity cause increased power loss in the low-shear Fontan circulation. Methods: Pulmonary vascular geometry was segmented from clinical cardiac MRI images. Pressure and velocity fields were then calculated using computational fluid dynamic simulations. Cardiac index was set at 2 L/min/m2 to simulate a low cardiac output state. A constant viscosity model (“Newtonian”) was compared to a shear-dependent viscosity model (“non-Newtonian”). Power loss was calculated by simplified power loss (using bulk flow and pressure changes) and viscous dissipation rate (using element-wise shear rates and viscosities). Both metrics were indexed to adjust for cardiac output and body surface area. Wilcoxon signed-rank test was used to compare differences between the two viscosity models. Results: Twenty patients (mean 10.9 years, 35% female) were included. Mean viscosity was nearly 10-fold higher in the non-Newtonian vs. Newtonian simulations (mean non-Newtonian to Newtonian viscosity ratio 9.7, SD 0.6). Accordingly, power loss by both metrics was significantly larger for the non-Newtonian simulations ( Figure ). Conclusions: Shear-dependent increases in blood viscosity cause increased power loss in computational models of the Fontan circulation under low cardiac output conditions. Further studies are needed to evaluate the degree to which this correlates with clinical outcomes.

A novel robust bounded control with inequality constraints and experimental validation for permanent magnet linear motor

In order to solve the problem that the trajectory of a permanent magnet linear motor may be out of bounds in practice and eliminate the influence of uncertainty on trajectory tracking, we propose a robust bounded control based on inequality constraints. First, the dynamics model of the permanent magnet linear motor is established, and then, the constrained output state variables are converted into unconstrained state variables by state conversion. Secondly, based on the dynamics model after state transformation, a novel control method containing both nominal and robust terms is proposed. Finally, the stability of the PMLM system is proved by the Lyapunov minimax method. Simulations and experiments with different algorithms are carried out on the PMLM system and the CSPACE platform. Based on the analysis of the experimental results, it can be found that robust bounded control based on inequality constraints can significantly improve the dynamic performance of the PMLM system and achieve high accuracy.

River system sediment flow modeling using artificial neural networks

Sediment leads to problems with navigation, agricultural productivity, and water pollution. The study of sediment flow in river reaches, which is a non-linear and complex process, is, thus, essential to addressing these issues. The application of artificial neural networks (ANN) to such problems needs to be investigated. For unsteady flow in a river system, river reach storage is an important variable that needs to be considered in data-driven models. However, previous research on sediment modeling did not involve the explicit use of storage variables in such models as is investigated in the current study. In the current study, storage variables have been explicitly (Model 2) used to predict the output state of the system at time ‘t + 1’ from the input state at time ‘t’ using ANNs. Sediment discharge at six gaging stations on the Mississippi River system, USA, has been considered as the state variable. The model has been compared with a model considering implicit variation of the storage parameter in the river system (Model 1). Dynamic ANNs are used for time-series datasets, which are more suitable for incorporating the sequential information within the dataset. Focussed gamma memory neural networks have been used in the current study. The numbers of hidden layers and hidden nodes, activation function, and learning rate have been varied step by step to obtain the optimal ANN configurations. The best selected input–output variables are those used in Model 2 as it performed slightly better than the other model in terms of Nash–Sutcliffe efficiency coefficient (CE) values. Model performance evaluated using normalized root mean square error (NRMSE) and CE shows satisfactory results. NRMSE was < 10% for all the outputs except for the Venedy and Murphysboro locations and CE values for sediment loads were > 0.45 for all locations except Murphysboro indicating acceptable performance by both the models. The models proved highly efficient (CE > 0.80, i.e., very good predictions) for predicting sediment discharge at locations along the main river channel with acceptable accuracy (CE > 0.45) for other locations and the storage change for the river system. These models can be used for real-time forecasting and management of sediment-related problems.

Passive Stabilization of Static Output Feedback of Disturbed Nonlinear Stochastic System

This paper investigates the Static Output (SO) control issue of the disturbed nonlinear stochastic system, which achieves passivity. Through the application of fuzzy sets and the stochastic differential equation, a Takagi–Sugeno (T-S) fuzzy model with the terms of multiplicative noise and external disturbance can be constructed to describe the considered systems. Furthermore, the Parallel Distributed Compensation (PDC) concept is used to design a fuzzy controller exhibiting an SO feedback scheme structure. To attenuate the effect of external disturbance, the PDC-based SO fuzzy controller is designed to exhibit passivity. During the derivation of some sufficient conditions, a line-integral Lyapunov function is utilized to avoid the conservative term produced using the derivative membership function. Using converting technologies, a stability criterion belonging to Linear Matrix Inequality (LMI) forms is proposed such that the derived conditions are convex hull problems and are solved through an optimization algorithm. Then, the proposed criterion is used to discuss the problem of SO controller design of ship fin stabilizing systems with added disturbance and noise.

Gene Expression Programming for Quantum Computing

We introduce QuantumGEP , a scientific computer program that uses gene expression programming (GEP) to find a quantum circuit that either (1) maps a given set of input states to a given set of output states or (2) transforms a fixed initial state to minimize a given physical quantity of the output state. QuantumGEP is a driver program that uses evendim , a generic computational engine for GEP, both of which are free and open source. We apply QuantumGEP as a powerful solver for MaxCut in graphs and for condensed matter quantum many-body Hamiltonians.

Prenatal features of aneurysm of the posterior cerebral artery: a case report

BackgroundFetal cerebral aneurysm other than aneurysm of vein of Galen aneurysmal malformation (VGAM) is extremely rare. This report describes prenatal features of aneurysm of the posterior cerebral artery (APCA) with rapid progression and its natural intrauterine course of the disease, which has never been reported.Case presentationThis is the first report of prenatal features of APCA, detected at 34–36 weeks of gestation, simulating choroid plexus cyst or arachnoid cyst. The diagnosis was based on color flow ultrasound with tracing along the course of cerebral arteries. Also, rendered 3D color flow ultrasound was helpful in demonstrating course of the vessels feeding the aneurysm and supporting the diagnosis. The aneurysm showed nature of rapidly progressive changes, leading to leakage resulting in intracerebral and intraventricular hemorrhage as well as high output state associated with anemia. Prenatal diagnosis and management are very challenging. This case ended up with planned delivery at 37 weeks, giving birth to a surviving male newborn, weighing 2600 g. The neonatal CT brain scans and CTA confirmed the prenatal findings. The prognosis was relatively poor because of extensive intracerebral hemorrhage with severe hydrocephalus and brain midline shift. The couple opted for neonatal palliative care without neurosurgical correction.ConclusionThis study demonstrate that the most important tool for prenatal diagnosis is color Doppler ultrasound, which will demonstrate turbulent blood flow. Three-dimension color Doppler ultrasound is helpful in supporting the diagnosis. The case presented here suggests that the disease has a natural course of rapid progression and massive brain destruction or high output congestive heart failure can be expected.

Prescribed-time control for hypersonic morphing vehicles with state error constraints and uncertainties

This paper focuses on the attitude control problem of hypersonic morphing vehicles (HMVs) with output state constraints and uncertainties in morphing phase. The main contribution of this work is not only realizing arbitrarily predefined settling time based on accelerated tracking rate but also ensuring smooth control performance under morphing effects and uncertainties. Firstly the control-oriented model is established based on the dynamic model of HMVs. Then, a prescribed-time disturbance observer (PTDO) is developed to enhance the robustness of flight control system based on radial basis function neural networks (RBFNN), allowing the lumped disturbances to be estimated within appointed time. Subsequently, based on tangent-type barrier Lyapunov function (TBLF) and prescribed-time convergence technique, the controller is designed via backstepping method, and the tracking errors of output states converge to the near origin within arbitrarily prescribed time without violating the preassigned constraints during tracking process. Finally, the closed-loop stability is ensured via Lyapunov synthesis, and numerical test results are presented to demonstrate the effectiveness of the proposed control scheme. Simulation results show that superior performance is obtained in terms of both transient process and stabilization.

The impact of saturable absorber recovery time on hybrid mode-locked fiber lasers with near zero net dispersion

The hybrid mode-locking scheme holds great potential in obtaining high power ultrashort laser source since it overcomes low damage threshold, self-starting difficulty in single real saturable absorber (SA) or artificial SA mode-locking scheme. Here we numerically studied the effect of SA’s recovery time on the stability of laser output in an all polarization-maintaining (PM) Erbium-doped fiber laser with hybrid mode-locking scheme, operating at the near zero net dispersion. The mapping relationship between fiber fused angles of nonlinear polarization rotation (NPR) section and different mode-locking states is demonstrated. The proportion of stable single pulse operating points increased from 7 % to more than 77 %, as the recovery time of the SA was reduced from 10 ps to 0.1 ps. The results indicate that the laser output states with hybrid mode-locking scheme could be highly affected by the SA recovery time, when the cavity net dispersion is in near zero regime.

Protecting steered coherence in squeezed generalized amplitude damping channel with memory

We investigate the average steered coherence (ASC) and maximal steered coherence (MSC) of two qubits in a squeezed generalized amplitude damping channel modeled by a squeezed thermal bath with dissipation and memory. By considering the input Bell states, it is shown that while the dissipation and thermal effects induce decay of the ASC and MSC in the output states, the squeezing effect suppresses their decay in the strong (full) squeezing region for the input even-parity (odd-parity) Bell states. Besides, the memory effect due to correlated actions of the channel can also be exploited for suppressing decay of the ASC and MSC.

Neural networks-based adaptive output-feedback control design for nonlinear systems with dead zone output and uncertain disturbances

This work focuses on the issue of neural networks-based adaptive output-feedback control for nonlinear systems with dead zone output and immeasurable states. Radial basis function neural networks (RBFNN) are utilised to approximate the unknown functions and an input-driven filter is used to estimate the immeasurable states. Nussbaum function is employed to address the issue of uncertain virtual control coefficient, which is brought by the dead zone in the output mechanism, and the presented control scheme requires only one adaptive law, making the structure of the controllers very realistic. Based on the approximation capabilities of NNs and the backstepping method, an adaptive controller is designed. Based on the Lyapunov stability theory, all signals in closed-loop systems are semi-globally uniformly ultimately bounded (SGUUB), and the tracking error converges to a small area near the origin. The effectiveness of the proposed adaptive control method is proved with the help of two examples.

Optical Metasurfaces for Tunable Vortex Beams

AbstractThe pursuit of device miniaturization and the generation of complex output responses has driven the development of optically tunable metasurfaces. Among these advancements, metasurface‐based vortex beams (VBs) have emerged as promising optically tunable knob technology due to their infinite output states through various orbital angular momentum (OAM) modes. In this study, the metasurface‐based VBs are successfully fabricated with exceptionally high OAM modes of 32 and 16, carefully examined using the Mach‐Zehnder interferometer. Throughout this study, these devices are referred to as infinite‐OAM meta‐knobs (IOMKs). The optical tunability of IOMKs is demonstrated by illuminating them with incident light possessing diverse degrees of freedom, including different polarizations and wavelengths. Furthermore, the interference nature of the IOMKs is experimentally explored by incorporating them into interference eraser measurements, providing an additional degree of freedom to the optical knob. In the interference eraser experiment, the broadband capability and the high reproducibility of the IOMKs with the OAM modes of 32 and 16 at three distinct wavelengths of 450, 530, and 610 nm is demonstrated. These findings represent a significant step toward understanding the potential applications of IOMKs in quantum optics and their promising role in the generation of complex output states.

Active arc suppression based MMC-HVDC DC fault adaptive reclosing

DC fault arcs continue to burn for a certain period under line residual energy (LRE) excitation, and existing DC fault reclosing has to wait for the DC arc to extinguish, resulting in a slow system recovery due to the long arc dissociation time. To address this problem, adaptive reclosing with active arc suppression (AAS) is proposed to speed up fault recovery. Firstly, a strategy is given for coordinating DC circuit breakers to quickly control the ground switch (GS) to switch between input and output states. Secondly, the positive effect of GS changing the line endpoint characteristics to achieve the AAS function on reducing the LRE content is revealed. In addition, a multiple AAS coordination method is given for different DC arc extinguishing speeds. Further, after each AAS, the voltage difference between permanent and non-permanent faults is mapped using the Pearson correlation coefficient to determine non-permanent faults. Compared with other typical reclosing, the proposed adaptive reclosing can actively shorten the arc dissociation time, reduce the power outage time to 13.5%–30%, which effectively improves the successful probability of fault reclosing, and prevents the MMC from restarting under non-permanent fault.

Effect of entanglement in the generalized photon subtraction scheme

The paper considers the possibility of generating different non-Gaussian states using the entangled state photon measurement scheme. In the paper, we have proposed a way to explicitly find the wave function and the Wigner function of the output state of this scheme. Moreover, the solutions found are not restricted to any particular case, but have maximum generality (depend on the number of measured photons and on all parameters of the scheme). Such a notation allowed us to carry out a complete analysis of the output states, depending on the scheme parameters. Using explicit expressions, we have analyzed the magnitude of non-Gaussianity of the output states, and we have revealed which particular states can be obtained in the proposed scheme. We have considered in detail a particular case of measurement (single photon measurement) and have shown that using explicit expressions for the output state wave function one can find scheme parameters to obtain states suitable for quantum error correction codes with a large fidelity value and high probability. The Schrodinger’s cat state with amplitude α = 2 can be obtained with fidelity F ≈ 0.88 and probability 18 percent, and the squeezed Schrodinger’s cat state (α = 0.5, R = 1) with fidelity F ≈ 0.98 and probability 22%.

An Objective Holographic Feedback Linearization Based on a Sliding Mode Control for a Buck Converter with a Constant Power Load

As a typical load, the constant power load (CPL) has negative impedance characteristics. The stability of the buck converter system with a mixed load of CPL and resistive load is affected by the size of the CPL. When the resistive load is larger than the CPL, the buck converter with the output voltage as an output function is a non-minimum phase nonlinear system, because its linear approximation has a right-half-plane pole. The non-minimum phase characteristic limits the application of many control techniques, but the objective holographic feedback linearization control (OHFLC) method is a good control strategy that can bypass the non-minimum phase system and make the system stable. However, the traditional OHFLC method, in designing the controller, generally uses a linear optimal quadratic design method to obtain a linear feedback control law. It requires a state quantity component with a one-order relative degree to the system. But it is not easy to find such a suitable state quantity with a one-order relative degree to the system. In this paper, an improved OHFLC method is proposed for Buck converters with a mixed loads of CPL and resistive loads, using the sliding mode control (SMC) theory to design the controller, so that the output state quantity components with different relative degrees to the system can be used in the holographic feedback linearization method. Finally, the simulation and experimental results also demonstrate that this method has the same, or even better, dynamic response performance and robustness than the traditional OHFLC method.

Controlled cyclic remote preparation

Multi-party quantum communication has gradually attracted widespread attention. To realize the perfect transmission of quantum states among multiple participants, a novel multi-party controlled cyclic remote preparation protocol for arbitrary single-qubit states with three senders is proposed. With the permission of one controller, each sender can transmit an arbitrary single-qubit state to its neighbor. In addition, we give a universal protocol for multi-party controlled cyclic remote preparation of arbitrary single-qubit states in the case of multiple senders, which can realize deterministic cyclic preparation of multiple quantum states in one direction. The scheme shows that the communication task can be successfully achieved only if all senders cooperate with the controller, and there is no need for the senders to employ information splitting and additional operations before performing measurements. Finally, we discuss the cyclic remote preparation protocol with three senders under five types of noisy environment, and the closeness between the output state and original state is measured by calculating fidelity.

Reversing Unknown Qubit-Unitary Operation, Deterministically and Exactly.

We report a deterministic and exact protocol to reverse any unknown qubit-unitary operation, which simulates the time inversion of a closed qubit system. To avoid known no-go results on universal deterministic exact unitary inversion, we consider the most general class of protocols transforming unknown unitary operations within the quantum circuit model, where the input unitary operation is called multiple times in sequence and fixed quantum circuits are inserted between the calls. In the proposed protocol, the input qubit-unitary operation is called 4 times to achieve the inverse operation, and the output state in an auxiliary system can be reused as a catalyst state in another run of the unitary inversion. We also present the simplification of the semidefinite programming for searching the optimal deterministic unitary inversion protocol for an arbitrary dimension presented by M. T. Quintino and D. Ebler [Quantum 6, 679 (2022)2521-327X10.22331/q-2022-03-31-679]. We show a method to reduce the large search space representing all possible protocols, which provides a useful tool for analyzing higher-order quantum transformations for unitary operations.

LIMDD: A Decision Diagram for Simulation of Quantum Computing Including Stabilizer States

Efficient methods for the representation and simulation of quantum states and quantum operations are crucial for the optimization of quantum circuits. Decision diagrams (DDs), a well-studied data structure originally used to represent Boolean functions, have proven capable of capturing relevant aspects of quantum systems, but their limits are not well understood. In this work, we investigate and bridge the gap between existing DD-based structures and the stabilizer formalism, an important tool for simulating quantum circuits in the tractable regime. We first show that although DDs were suggested to succinctly represent important quantum states, they actually require exponential space for certain stabilizer states. To remedy this, we introduce a more powerful decision diagram variant, called Local Invertible Map-DD (LIMDD). We prove that the set of quantum states represented by poly-sized LIMDDs strictly contains the union of stabilizer states and other decision diagram variants. Finally, there exist circuits which LIMDDs can efficiently simulate, while their output states cannot be succinctly represented by two state-of-the-art simulation paradigms: the stabilizer decomposition techniques for Clifford + T circuits and Matrix-Product States. By uniting two successful approaches, LIMDDs thus pave the way for fundamentally more powerful solutions for simulation and analysis of quantum computing.

Topological polarisation states

Polarisation states are described by spin expectation values, known as Stokes parameters, the trajectories of which in a rotationally symmetric system form a sphere named after Poincaré. Here, we show that the trajectories of broken rotational symmetric systems can exhibit distinct topological structures in polarisation states. We use a phase-shifter to form a polarisation circle(S1), which interferes with the original input due to the phase change of the output state upon rotation. By rotating the circle using a rotator, the trajectories become a polarisation torus(S1×S1), which was experimentally confirmed in a simple setup using passive optical components together with the Mach–Zehnder interferometer. We also discuss the realisations of other topological features, such as a Möbius strip, a trefoil knot, Hopf links, and topological Dirac bosons, with a bulk-edge correspondence.

Leader-follower formation control of Euler-Lagrange systems with limited field-of-view and saturating actuators: A case study for tractor-trailer wheeled mobile robots

In this paper, an adaptive-neural constrained controller is proposed for a group of Tractor-trailer wheeled mobile robots with limited field-of-view (FOV) constraints and saturating actuators. With an effective combination of the asymmetric Barrier Lyapunov function based control design and dynamic surface control in the proposed constrained controller, the limited FOV constraints are not transgressed the predefined and limited bounds. The risk of the actuators saturation is extremely decreased through restricting amplitudes of the output states errors. It is proved that all the output states in the closed-loop system are semi-globally uniformly ultimately bounded and the relative distance and orientation angles errors are converged in the limited and preassigned boundaries. Compared with the existing results, the proposed constrained controller not only assures that these states errors between consecutive TTWMRs are bounded, but also all the output states errors converge to a small region around zero in a fixed-time that this issue accelerates the convergence speed rate and improves the transient response performance of the perfect tracking control for all TTWMRs.